Means for feeding a tool



Aug. 23, 1955 w. DARBY WANS FOR FEEDING A TOOL 2 Sheets-Sheet l Filed March 9, 1954 fl ia V Aug. 23, 1955 w. DARBY ,896

MEANS FOR FEEDING A TOOL Filed March 9, 1954 2 Sheets-Sheet 2 ll Illllil Illll 16 l IS A B E F H FIGS.

//WA/r06 United States Patent lVlEANS FQR FEEDING A TOOL Walter Darby, Coventry, England, assignor of one-half to Stuart Davis Limited, Coventry, England Application March 9, 1954, Serial No. 415,022

Claims priority, application Great Britain March 24, 1953 7 Claims. (Cl. 125-11) The invention relates to means for feeding a tool of the kind which is to be traversed in one direction across a work-piece in operative contact therewith and to be returned, clear of the work-piece, in readiness for repeating the operative traverse. Although not limited in this respect the invention is particularly adapted for use where the tool is a hardened steel, peripherally-ribbed roller for crushing a screwthread-grinding rib in a grinding wheel, or is a diamond tool for dressing such a rib of a grinding wheel. In such a use, it is important to relieve from undue pressure any parts which are for eifecting the feed and have a frictional engagement with each other; also, when using a crushing roller, to avoid breaking material away from the edges of the grinding wheel; and the object of the invention is a means for enabling these desiderata to be achieved.

According to the invention the tool is fed, in a desired manner relatively to the work-piece during the operative traverse and return movements, by the conjoint action of a pivoted cam member and a slidable cam member, the slidable cam member being parallelly slidable relatively to the pivoted cam member for positioning the tool for the operative traverse and return movements, and the pivoted cam member being supported from a stationary part so as to be engaged between the slidable cam member and a follower operatively connected to the tool whereby the latter will be fed dependently on the integration of the engaged surfaces of the two cam members.

According to a further feature the slidable cam member is operated with lost motion relatively to the operative traverse and return movements of the tool whereby to delay, until the tool reaches a predetermined position during one of those movements, the interaction of cam surfaces of the said members.

In the drawings:

Figure l is an isometric view of part of a machine embodying a hardened steel, peripherally-ribbed roller which is to be fed, in accordance with the invention, for crushing a screw-thread-grinding rib in a grinding wheel, the latter not being shown in the figure;

Figures 2 to 4, inclusive, are diagrams approximating plan views of a portion of Figure l and showing three phases of the interaction of the cams, Figures 2 and 3 respectively showing their relative positions at the start and at a position intermediate of the operative traverse of a crushing operation, and Figure 4 showing the positions at the finish of the operative traverse and prior to the return traverse; and

Figure 5 is a diagram indicating the path of the crushing roller during the complete cycle.

In Figure 1, the crushing roller is shown journalled on a shaft 11 of which the ends are held, by respective blocks 12, to a lever 13, the latter having aligned V- grooves (only one of which is shown) which coact with part-cylindrical grooves in the blocks for holding the shaft in position, and the blocks being held to the lever by screws 14.

The lever 13 lies between cheeks 15, 15 of a traverse slide, being pivoted at the foot on a pin 16 Whose ends are fast in the cheeks, and the slide is supported for reciprocating movement on a guide 17 which is made fast, as by screws 18, with stationary parts 19, 19 of the machine. These stationary parts are fast with another stationary part 2-8 with guides 21, 21, at right-angles to the guide 17, for a second slide 22, the latter supporting a sinebar 23 for driving the traverse slide. This drive, which is the subject of application Serial No. 415,023, involves biassing the traverse slide for a shoe (not shown) on it to engage the sine-bar so that vertical motion of the slide 22 is translated into a transverse motion of the traverse slide. The sine-bar is pivoted near its foot to the slide 22, and fast with the latter are two blocks 22a and 221) between which the head of the sine-bar extends. A screw in the block 2212 holds the sine-bar against a substitutable gauge piece 22c which sets the angle of the sine-bar for controlhng the amplitude of the traverse slide.

The head of the lever 13 is forked to provide cheeks 24, 24 between which the cam follower 25 is pivotally supported on a pin 26, and the lever is biassed by tension springs 27, 27 to urge a vertical operative edge 28 of the follower towards a pivoted cam 29. As shown, the springs 27, 27 are held at their inner ends by anchor pins 30 (of which only one can be seen) extending between the adjacent cheek 15 and a central stationary part 31, and their outer ends are held by pins 32, 32 whose end portions engage in grooves which are at the outer side of the lever and at each side of respective recesses, accommodating the springs, in the top of the lever. The part 31 acts as a stop to limit inward movement of the lever when, as hereinafter described, the cam 29 is clear of the edge 28 of the follower.

The cam 29 is pivoted, at 33, between lugs 34 and 35 of a bracket 36 which is secured at its ends by screws 37, 37 to the stationary parts 19, 19, this bracket providing, in conjunction with parts 19, a guide for a slidable cam member 38. The opposed surfaces of the parts 19 and the central portion of the bracket 36 provide two opposite sides of the guide, and the intermediate sides of the guide are provided by the underside of the lugs 34 and the tops of the bracket end portions engaged by the screws 37. The bracket also has a window 39 through which the operative portion of the pivoted cam 29 can extend for coaction with the slidable cam member. Due to the pivot 33 being at right-angles to the pin 26, the operative edge 28 of the follower 25 can always make continuous line contact with the adjacent surface of the cam 29.

At each end the traverse slide has lugs 40, 40 which support screws 41, 41 for coaction, in the manner hereinafter described, with the adjacent ends of the slidable cam member 38, these screws being locked in adjusted positions by set-screws 42, 42.

During vertical reciprocation of the second slide 22 the sine-bar 23 imparts horizontal reciprocation to the traverse slide relatively to the guide 17, and during the traverse the cams 29 and 33 coact with the follower 25 for feeding the crushing roller 10 radially into and out of engagement with the grinding wheel. These feeding movements are explained with reference to Figures 2 to 5, to which reference will now be made.

The commencement of the operative traverse is illustrated by Figure 2, in which a heel 29a of the pivoted cam 29 is shown engaging the adjacent fiat surface 38a of the slidable cam member. When the traverse slide 15, 15 is driven towards the right of the figure the edge 28 of the follower 25 engages the face 43 of the pivoted cam to tilt the lever 13 against the springs 27, 27, for feeding the crushing roller into crushing engagement with the grinding wheel 44. At the moment this crushing engagement takes place, the roller overlaps the adjacent Wheel edge.

A continuation of the operative traverse movement brings the follower edge 28 on to the surface 45, which is held parallel to the traverse movement of the pivoted cam 29 as shown by Figure 3 for maintaining the crushing engagement until the left-hand screw 41 engages and moves the slidable cam member 38 to the position shown in Figure 4, in which latter the heel is shown as having been'urged, by the effort of the springs 27, 27 acting on the edge .28, into a recess 47 of the slidable cam member 38 V Simultaneously with the entry of the heel into the recess 47, the edge 28 rides up a surface 46 of the pivoted barn. The heel and recess 47 have coacting, inclined surfaces 48 and 49 respectively, and the effect of these, in conjunction with the surface 45, is to cause the follower to retract the crushing roller from the grinding wheel at a faster rate than they were fed into engagement. The relative positions of the parts at the end of the "operative traverse is shown by Figure 4, and it will be seenthat when the return movement (i. e., towards the left of that figure) of the traverse slide occurs the edge 28 passes clear of the pivoted cam, and the right-hand screw engages the slidable cam member to restore it to the position shown in Figure 2. The movement of the slidable cam member to this position moves the heel 29a out of the recess 47 due to the interaction of the surfaces 48 and 49, as also shown in Figure 2, in readiness for the next operative traverse movement.

The path imposed on the crushing roller by the conjoint action of the earns 29 and.38 during the operative traverse and return movements is indicated by Figure 5.

'Thus, the initial portion of the operative traverse movethe actual crushing stroke is indicated by the line C-D;

the retraction of the crushing roller from the grinding wheel isshown' bythe line D-E; and the completion of the operative traverse is represented by the line EF. The return movement is a straight-line one from F to A.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. Means for feeding 'a crushing roller which isto be traversed in one direction across a grinding wheel, to

returned clear of the grinding wheel in readiness for a repetitionof the cycle, including a reciprocable carrier for said roller, 2. firstcam member, stationary guide means supporting said first cam member for sliding in the direction of the operative and return traverse movements of, said carrier, means on said carrier for engaging and sliding said first cam member after the commencement of both'said movements, a lever pivotally supported adjacent 'beQtreated, in operative contact therewith and to be 7 one end from said carrier, said roller journalled from said 'lever in a position intermediate the ends of the latter, a

follower operatively connected to the other end of said lever, a second cam member interposed between said follower and said first earn a stationary part, a pivot on said stationary part and engaging said second cam member for pivotally supporting the latter, said first cam member having a surface which, when said first cam member is in one extreme position, holds said second cam member to be in the path of said follower, whereby the latter can feed said roller into working contact with said grinding, wheel during the operative traverse, and said first cam member having a second cam surface which, when said first cam member is in its opposite extreme position, permits said second cam member to move out of the path of said follower whereby the roller can be disengaged from said grinding wheel during the return traverse movement.

2. Means for feeding a crushing roller which is to be 4 traversed in one direction across a'grinding wheel, to be treated, in operative contact therewith and to be returned clear of the grinding wheei in readiness for a repetition of the cycle, including a reciprocable carrier for said roller, a first cam member, stationary guide means supporting said first cam member for sliding in the direction of the operative and return traverse movements of said carrier, means on said carrier for engaging and sliding said first cam member after the commencement of both said movements, a lever pivotally supported adjacent one end from said carrier, said roller journalled from said lever in a position intermediate the ends of the latter, a follower operatively connected to the other end of said lever, a second cam member interposed between said follower and said first earn a stationary part, a pivot on said stationary part and engaging said second cam member for pivotally supporting the latter, said first cam member having a surface which, when said first cam member is in one extreme position, holds said second cam member to be in the path of said follower, and cam surfaces on said second cam member for coaction with said follower, whereby the latter can feed. said roller into working contact with said grinding wheel during the operative traverse, and said first cam member having a second cam surface which, when said first cam member is in its opposite extreme position, permits said second cam member to move out of the path of said follower whereby the roller can be disengaged from said grinding wheel during the return traverse movement, the movement of said follower being in dependence on the instantaneous integration of the cam surface it engages of said second cam member and said interengaging cam surfaces of both cam members. 7

3. Crushing roller feeding means, according to claim 2, in which the slidable cam member is engageable, with lost motion, by a part partaking of the full traverse movements whereby to delay, until the tool reaches a predetermined position during those movements, the interengagement of certain cam surfaces of the cam members.

4. Means for feeding a crushing roller which is to be traversed in one direction across a grinding wheel, to be treated, in operative contact therewith and to be returned clear of the grinding wheel in readiness for a repetition of the cycle, including a reciprocable carrier for said roller, a traverse slide, a first cam member, stationary guide means supporting said first cam member for sliding parallel to the line of movement of said carrier, spaced means fast with said carrier, said first cam member posi tioned in the path of said spaced means to be slid thereby during said movements, said spaced means spaced wider apart than the length of said first cam member whereby to operate it with lost motion, a lever pivoted at one end from said carrier on an axis parallel to said traverse movements, said roller journalled from an intermediate point of said lever, a follower operatively connected to the other end of said lever, a second cam member interposed between said follower and said first cam a stationary part, a pivot on said stationary part and engaging said second cam member for pivotally supporting thelatter, said first cam member having a surface which, when said first cam member is in one extreme position, holds said second cam member to be in the path of said follower, and cam surfaces on said second cam member for coaction with said follower, whereby the latter can feed said roller into working contact with said grinding wheel during the operative traverse, and said first cam member having a second cam surfacewhich, when said fi"st cam member is in its opposite extreme position, permits said second cam member to move out of the path of said follower whereby the roller can be disengaged from said grinding wheel during the return traverse movement, said foliower to be moved for feeding said crushing roller by the cam surface of said second cam member engaged by said follower, as modified by the position about its pivotal support of said second cam member due to the interaction of said interengaging cam surfaces during the sliding of said first cam member.

5. Crushing roller feed'mg means, according to claim 4, in which the follower is pivoted from the lever on an axis which is parallel to the lever pivot axis and has an elongated operative edge, for coaction with the second cam member, which is at right-angles to its pivot axis whereby to maintain said follower in a correct attitude relatively to said second cam member during pivoting movement of said lever.

6. Means for feeding a peripherally-ribbed crushing roller which is to be traversed in one direction across a grinding Wheel, to be treated, in operative contact therewith for crushing a thread-grinding rib in said grinding wheel and to be returned clear of the grinding wheel in readiness for a repetition of the cycle, including a reciprocable carrier, said crushing roller journalled in said carrier, at first cam member, stationary guide means supporting said first cam member for sliding parallel to the line of movement of said carrier, spaced means fast with said carrier, said first cam member positioned in the path of said spaced means to be slid thereby during said movements, said spaced means spaced wider apart than the length of said first cam member whereby to operate it with lost motion, a lever pivoted at one end from said carrier on an axis parallel to said traverse movements, said roller journalled from an intermediate point of said lever, a follower operatively connected to the other end of said lever, a second cam member interposed between said follower and said first cam a stationary part, a pivot on said stationary part and engaging said second cam member for pivotally supporting the latter, a first pair of interengageable surfaces on said members which at the start of the operative traverse hold said second cam member in the path of said follower, a second cam surface on said second cam member engaged by said follower after the start of said operative traverse for feeding said roller into operative engagement with said grinding wheel, a third cam surface on said second cam member permitting said follower to allow disengagement of said roller and wheel at a later stage in said operative traverse, a second pair of interengageable surfaces on said cam members permitting said second cam member to move about its pivotal support to be out of the path of said follower when said first cam member has been slid in the direction of the operative traverse by one of said spaced means, the latter being for sliding said first cam member for said second pair of interengageable surfaces to engage at said later stage whereby the disengagement of said roller and wheel depends on an integration of the movement of said follower along said third cam surface and the pivotal movement of said second cam member consequent on the engagement of said second pair of interengageable cam surfaces, said second cam member being maintained in a position out of the path of said follower during the return movement of said traverse slide until said follower has passed said third and second cam surfaces.

7. Crushing roller feeding means, according to claim 6, in which the other spaced means engages the first cam member towards the end of the return movement of the carrier whereby to slide said first cam member for the first pair of interengageable surfaces to be engaged for returning the second cam member to be in the path of the follower in readiness for another operative traverse.

References Cited in the file of this patent UNITED STATES PATENTS 2,342,792 Dare Feb. 29, 1944 FOREIGN PATENTS 461,223 Great Britain Feb. 12, 1937 865,920 France Mar. 17, 1941 

